Restrict solidity function as only callable by another function

Question

How can I make a solidity function to be only callable by other functions in the same contract? and it doesn't visible in etherscan or remix as a normal function.

Eg:

contract Calc {
      function add(uint a, uint b) public returns(uint) {
                return adder(a,b);
             }
      function adder(uint a, uint b) public returns(uint) {
                return (a+b);
          }

}

here I need to make the function 'adder' is only accessible to other function like 'add'. but i can't be accessed by the user through remix or etherscan

Answer 1

function adder(uint a, uint b) public returns(uint) {
                return (a+b);
          }

simply change the visibility of your adder function from public to internal or private

public means the function is accessible from the inside and outside.

internal means the function is accessible only from within the contract himself and contracts inheriting from that contract.

private means the function is only callable within the very smart contract.